Improve fail_under by enabling more refined control on threshold

[nedbat]

Originally reported by Anonymous

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Hello,

I didn't find this option anywhere in the documentation so i hope i haven't missed anything.
The idea is that right now we can only set a global minimum threshold percentage on coverage. While this is really useful i suggest coverage could provide a more refined control on this requirement such as per module minimum percentage.

Taking for example jest (https://facebook.github.io/jest/docs/en/configuration.html#coveragethreshold-object) it would be really great if i could set in the report section my requirements like maybe a list of regexes with minimum requirements.

• api/* -> 40%
• db/* -> 80%

Thanks in advance

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• Bitbucket: https://bitbucket.org/ned/coveragepy/issue/666

[nedbat]

Interesting idea, but it seems very specialized for something like coverage. A separate tool could look at the coverage report, and make this kind of assessment. Would that work for you?

[nedbat]

Original comment by Orestis Ioannou (Bitbucket: oorestisime, GitHub: oorestisime)

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I guess so yes, do you have a tool in mind?

[nedbat]

Original comment by Orestis Ioannou (Bitbucket: oorestisime, GitHub: oorestisime)

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Maybe this could be added to pytest-cov although i am not sure whether they would want this or if it is better to support this kind of feature directly in coverage so that all the runners could benefit from it.

[nedbat]

I don;t have a specific tool in mind. It could even be a new tool that you run after coverage, to make a detailed assessment of the results. It doesn't have to be added to anything existing.

[nedbat]

Original comment by Orestis Ioannou (Bitbucket: oorestisime, GitHub: oorestisime)

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ok right, if you are nonetheless willing to let this go in coverage i could have a look on how to implement this and propose a PR. otherwise i guess i should close the issue :)

[nedbat]

A JSON report (#720) would make it possible to implement this feature, especially if it included sub-totals for each directory of code.

[nedbat]

See https://nedbatchelder.com/blog/202111/coverage_goals.html for some progress on a tool to do this.